1. Field of the Invention
The present invention relates to a liquid crystal display control device and a method of preparing patterns for the same device.
2. Description of the Related Art
A frame modulation gradation display method has been known as the gradation display method of a matrix type liquid crystal display panel (LCD panel). According to the above frame modulation method, gradation display is possible on the LCD panel even if a single pixel only makes binary display (on display and off display). According to the frame modulation method, on display and off display are properly combined in the time axis direction, and thereby, pseudo gradation display is possible. For example, if a 16-gradation level image is displayed, 16 frames are set as one cycle, and on frame and off frame are determined in accordance with gradation level. As a result, a desired gradation is obtained as the mean value of 16 frames.
As described above, according to the frame modulation method, several frames are set as one cycle. For this reason, the number of gradation levels increases, and thereby, flicker conspicuously appears; as a result, display quality worsens. Thus, if the 16-gradation level image is displayed, a display pattern is formed using 4 horizontal direction pixels and 4 vertical direction pixels, that is, the total 4×4=16 pixels. By doing so, the display quality can be prevented from deteriorating.
The following is a description on memory capacity required for storing the above display pattern. For example, if the 16-gradation level image is displayed, the following memory capacity is required. The memory capacity is 4096 bits=16 (the number of pixels in a display pattern)×16 (the number of frames)×16 (the number of gradation levels). If a microcomputer having built-in memory performs display control, preferably, the number of bits for storing the display pattern is reduced as much as possible because the number of bits of the built-in memory is limited.
In the frame modulation method, the display pattern for each gradation level is not necessarily optimized. For this reason, there is a problem that display quality worsens.
As described above, conventionally, there are problems that the memory capacity for storing the display pattern becomes much, and the display pattern is not optimized.